In the case of infectious diseases such as septicemia, administration of adequate antibacterial agents at an early stage is critical for treatment or prognosis of a patient. According to conventional techniques, infectious diseases such as septicemia have been tested in the manner described below.
The blood sampled from a patient (2 to 10 ml) is inoculated into about 30 to 100 ml of a liquid medium for bacterial culture, and culture is then conducted at 30° C. to 37° C. On the basis of changes in the turbidity of the medium, generation of gas in the medium caused by bacteria, changes in pH levels, and other factors as indicators, observation is continued for 1 to 7 days until bacterial growth is detected. After the bacterial growth is observed, the culture solution is collected and subjected to gram staining and subculture (secondary culture). Bacterial species are roughly classified on the basis of the results of gram staining, and whether a single type of bacteria or plural types of bacteria are detected is determined. When colonies of the bacteria grown via subculture are homogeneous, it is hypothesized that a single type of bacteria is present in the blood, and the bacteria are then subjected to the identification test and the sensitivity test. When a plurality of types of bacteria are observed as a result of gram staining or colonies of apparently different configurations are grown, in contrast, each colony is picked, and culture is continued until colonies of a single configuration are selectively grown. That is, it takes a number of days to complete a procedure from sampling of specimens to identification thereof. In the case of a patient suspected of septicemia, early diagnosis and administration of an adequate antibacterial agent are critical for prognosis of the patient. As a method that enables more accurate identification of bacterial species within a shorter period of time, accordingly, an immunological technique, such as immunochromatography, is employed (WO 2007/069673). When bacteria are identified via an immunological technique, an immunoglobulin that specifically recognizes a protein of the target bacteria is to be bound. The bound immunoglobulin is labeled with colored latex particles or fluorescence materials in advance, so that the presence of bacteria can be detected. Thus, bacteria can be detected directly from blood culture without pure culture. However, specimens used for bacterial testing, such as the blood, culture solution, sputum, snivel, or stool, contain various types of proteins. In order to detect a target protein with high sensitivity, accordingly, it is necessary to remove contaminants by separating bacteria via centrifugation or culture on a solid medium. In addition, thermal treatment, cell membrane destruction with the aid of a solution, or other treatment may become necessary depending on the place where a protein of target bacteria is present, a protein configuration, or other factors.
Accordingly, special equipment, such as a centrifuge or heat block, was necessary, and a time-consuming procedure, such as culture, was necessary. In the case of centrifugation, furthermore, precipitated bacteria may erroneously be suctioned when discarding the supernatant, the number of bacteria may be reduced, and accurate judgment may not be made occasionally.